A phony sign language interpreter appeared to gatecrash a press conference about the arrest of a suspected serial killer, reportedly making signs that were complete nonsense.

As Tampa police Chief Brian Dugan announced the arrest of Howell Donaldson the interpreter, named as Derlyn Roberts has been accused of ‘waving her arms like she was singing Jingle Bells’.

As Mr Dugan was delivering a timeline of four shootings Donaldson is suspected of carrying out, the message Roberts conveyed was apparently gibberish.

Rachell Settambrino, who is deaf and teaches American Sign Language at the University of South Florida, told the Tampa Bay Times that she was “disappointed, confused, upset” and wanted to know why it had not been checked.

Gibberish – Derlyn Roberts has been accused of ‘waving her arms like she was singing Jingle Bells’ (Picture: YouTube)

According to her, the timeline of shootings was translated into: “Fifty-one hours ago, zero 12 22 (indecipherable) murder three minutes in 14 weeks ago in old (indecipherable) murder four five 55,000 plea 10 arrest murder bush (indecipherable) three age 24.”

“She sat up there and waved her arms like she was singing Jingle Bells,” she added.